How to implement half-width digital conversion function in php

In recent years, with the continuous development of Internet technology, PHP language has been widely used in Web development and has become one of the most popular Web programming languages. When programming in PHP, we often need to perform conversion operations on numbers. One of the important operations is to convert full-width numbers into half-width numbers. Below, we will introduce how to implement this function in PHP.

1. The difference between full-width numbers and half-width numbers

In Unicode, the full-width and half-width characters corresponding to the ten numbers 0 to 9 are as follows:

Full-width numbers: 0123456789

Half-width numbers: 0123456789

As you can see, the difference between full-width numbers and half-width numbers is that the former has a larger width and occupies two character positions, while the latter has a narrower width and only occupies one character Location. In web programming, since full-width numbers take up more space, we often need to convert them into half-width numbers.

2. Implementation method

In order to convert full-width numbers into half-width numbers, we can use PHP's built-in function mb_convert_kana(). This function is mainly used to convert Japanese half-width characters or full-width characters in characters. Among them, the method of converting full-width numbers to half-width numbers is as follows:

$half_width_str = mb_convert_kana($full_width_str, "n", "UTF-8");

mb_convert_kana() The parameters of the function are explained as follows:

• $full_width_str: The string to be converted must be UTF -8 encoding.
• "n": Converts all full-width characters to half-width characters.
• "UTF-8": Indicates the input/output character encoding, which must be the same as the string encoding.

The following is a complete sample code:

<?php
$full_width_str = "０１２３４５６７８９";
$half_width_str = mb_convert_kana($full_width_str, "n", "UTF-8");
echo "全角数字：" . $full_width_str . "<br/>";
echo "半角数字：" . $half_width_str . "<br/>";
?>

The output result is as follows:

全角数字：０１２３４５６７８９
半角数字：0123456789

Through the above code, we successfully converted full-width numbers into half-width numbers . It should be noted that when using the mb_convert_kana() function, you need to ensure that the input string is encoded as UTF-8, and the same encoding format needs to be maintained when outputting.

3. Summary

In Web development, converting numbers is one of the common requirements. For PHP programmers, converting full-width numbers into half-width numbers is a skill that must be mastered. This article introduces the use of PHP's built-in function mb_convert_kana() to convert full-width numbers to half-width numbers. I hope that all readers can master this skill and use it at any time in actual development work.

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